Antigen-specific cellular responses following mucosal vaccination.

Rats were vaccinated either i.t. (top panel) or orally (bottom panel) with either 105 CFU U112, 107 CFU U112ΔiglB, or mock-vaccinated with PBS, and rested for 14 or 28 days. Rats were euthanized and spleens (106 cells/well) and draining lymph nodes (CLN and MLN) collected (day 14: 5×105 cells/well and day 28: 1×105 cells/well). Single cells were cultured for 72 hr in the presence of approximately 1 µg of protein from either UV-inactivated U112 (for U112 and mock vaccinated groups), or UV-inactivated U112ΔiglB (for U112ΔiglB vaccinated group). Cells were then separated by centrifugation and supernatants were collected and assayed for IFN-γ production by ELISA (shown here in pg/mL, limit of detection is 30 pg/mL). Results are representative of two independent experiments at each time point. CLN = cervical lymph nodes, MLN = mesenteric lymph nodes, SD = standard deviation, NA = not applicable.